A federal appeals court on Friday rebuffed an effort by NYPD unions to keep alive an appeal of a ruling that found police stop-and-frisk practices unconstitutional and ordered reforms.

The ruling by the 2nd U.S. Circuit Court of Appeals appeared to clear the way for Mayor Bill de Blasio to move forward with a settlement agreeing to a three-year-long court monitorship to oversee changes in training, supervision and discipline.

Police unions wanted to keep the case alive, complaining that U.S. District Judge Shira Scheindlin's 2013 ruling that cops' engaging in a pattern of stopping minorities without adequate cause damaged officers' reputations and could interfere with contract rights.

But the three-judge panel yesterday said that in the wake of de Blasio's election, the unions were trying to launch a "collateral attack on the democratic process" that "could erode the legitimacy of decisions made by the democratically elected representatives of the people."

The panel gave the unions seven days to seek review by the full 2nd Circuit, but the Patrolmen's Benevolent Association, in a statement, did not signal any plans to appeal further.

"The PBA will continue to monitor actions taken in this process moving forward to ensure that they do not violate the rights of NYC police officers," said PBA president Patrick Lynch.

Scheindlin's decision was appealed last year by the Bloomberg administration. At that time, the same appeals panel stayed her ruling and removed her from the case for an appearance of bias. The case is now assigned to U.S. District Judge Analisa Torres.

Under the settlement, a court-appointed monitor will meet with stakeholders to develop detailed reforms and supervise stop-and-frisk practices for three years. Court oversight would end after five years if the city substantially complies with court orders.

Although it greenlighted the settlement, the 2nd Circuit panel cautioned that it was not endorsing or affirming Scheindlin's "complex and controversial" finding of rampant unconstitutionality that infuriated many cops.

"Nothing in this opinion should be construed as accepting or rejecting any part of the . . . orders issued by Judge Scheindlin," the judges wrote.